Selection of Optimal Threshold of Generalised Rock Quality Designation Based on Modified Blockiness Index

Table 4

MB_i values (%) of the 35 types of hypothetical models and the corresponding ratings.

Joint persistence (m)		Joint spacing (m)
		Extremely wide	Very wide	Wide	Moderate	Close	Very close	Extremely close
		0.02	0.04	0.13	0.4	1.3	4	6
40	Very high	93.7571	91.4286	61.2567	27.5231	17.5350	10.5002	0.3650
20	High	91.0728	87.5613	44.6782	23.9566	13.5002	0.3186	0.0307
10	Medium	90.2910	87.2045	44.0021	20.9621	4.6818	0.0573	0.0012
3	Low	88.9321	86.0180	43.8025	7.9657	0.1070	1.20E-8	1.78E-10
1	Very low	87.9759	84.3504	18.2843	0.1110	5.13E-5	1.03E-7	1.74E-9